Novel, highly potent systemic glucokinase activators for the treatment of Type 2 Diabetes Mellitus.

Glucokinase (GK, hexokinase IV) is a unique hexokinase that plays a central role in mammalian glucose homeostasis. Glucose phosphorylation by GK in the pancreatic ß-cell is the rate-limiting step that controls glucose-stimulated insulin secretion. Similarly, GK-mediated glucose phosphorylation in hepatocytes plays a major role in increasing hepatic glucose uptake and metabolism and possibly lowering hepatic glucose output. Small molecule GK activators (GKAs) have been identified that increase enzyme activity by binding to an allosteric site. GKAs offer a novel approach for the treatment of Type 2 Diabetes Mellitus (T2DM) and as such have garnered much attention. We now report the design, synthesis, and biological evaluation of a novel series of 2,5,6-trisubstituted indole derivatives that act as highly potent GKAs. Among them, Compound 1 was found to possess high in vitro potency, excellent physicochemical properties, and good pharmacokinetic profile in rodents. Oral administration of Compound 1 at doses as low as 0.03mg/kg led to robust blood glucose lowering efficacy in 3week high fat diet-fed mice.

Discovery of orally active hepatoselective glucokinase activators for treatment of Type II Diabetes Mellitus.

Systemically acting glucokinase activators (GKA) have been demonstrated in clinical trials to effectively lower blood glucose in patients with type II diabetes. However, mechanism-based hypoglycemia is a major adverse effect that limits the therapeutic potential of these agents. We hypothesized that the predominant mechanism leading to hypoglycemia is GKA-induced excessive insulin secretion from pancreatic ß-cells at (sub-)euglycemic levels. We further hypothesized that restricting GK activation to hepatocytes would maintain glucose-lowering efficacy while significantly reducing hypoglycemic risk. Here we report the discovery of a novel series of carboxylic acid substituted GKAs based on pyridine-2-carboxamide. These GKAs exhibit preferential distribution to the liver versus the pancreas in mice. SAR studies led to the identification of a potent and orally active hepatoselective GKA, compound 6. GKA 6 demonstrated robust glucose lowering efficacy in high fat diet-fed mice at doses ⩾10mpk, with ⩾70-fold liver:pancreas distribution, minimal effects on plasma insulin levels, and significantly reduced risk of hypoglycemia.

The discovery of a novel route to highly substituted α-tropolones enables expedient entry to the core of the gukulenins.

A simple and general method for the synthesis of highly substituted α-tropolone ethers that allows rapid access to the bis(tropolone) core of the antiproliferative metabolites (-)-gukulenins A and F (3, 4) is described. The reaction proceeds by thermolytic opening of gem-dibromobicyclo[4.1.0]heptane intermediates, which are readily accessed from simple starting materials. Mechanistic studies suggest the reaction proceeds via an autocatalytic process mediated by methyl hypobromite. This synthetic sequence allows access to a broad array of highly substituted α-tropolones.